Cobalt chromium alloy is a commonly used dental restorative material, the study of hardness variation trend is very important for the friction and wear analysis of artificial cobalt chromium alloy denture fabricated via selective laser melting (SLM). The influence rule of hardness of SLM formed cobalt chromium alloy from technological parameter is studied and a Vickers hardness model is established. Experimental results indicate that laser power is the mostly significant factor influencing the Vickers hardness of SLM cobalt- chromium alloy specimen, followed by scanning speed, and the minimal is scanning interval. The microstructure shows that along the building direction, grains grow in the shape of columnar with consistent direction and there is an obvious layer stack between the grains. The grain is grid-shaped and arranged uniformly and tightly in the perpendicular direction. As the laser energy density increases, the grain size and hardness of forming parts increase, but both of the microtexture density and hole-defect decrease significantly. Based on the experimental results comparison between the Vickers hardness, the rationality and validity of the Vickers hardness prediction model is verified.